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New Perspectives for QCD Physics at the LHC
I review a number of topics where conventional wisdom relevant to hadron
physics at the LHC has been challenged. For example, the initial-state and
final-state interactions of the quarks and gluons entering perturbative QCD
hard-scattering subprocesses lead to the breakdown of traditional concepts of
factorization and universality for transverse-momentum-dependent observables at
leading twist. These soft-gluon rescattering effect produce single-spin
asymmetries, the breakdown of the Lam-Tung relation in Drell-Yan reactions, as
well as diffractive deep inelastic scattering, The antishadowing of nuclear
structure functions is predicted to depend on the flavor quantum numbers of
each quark and antiquark. Isolated hadrons can be produced at large transverse
momentum directly within a hard higher-twist QCD subprocess, rather than from
jet fragmentation, even at the LHC. Such "direct" processes can explain the
observed deviations from pQCD predictions of the power-law fall-off of
inclusive hadron cross sections as well as the "baryon anomaly" seen in
high-centrality heavy-ion collisions at RHIC. The intrinsic charm contribution
to the proton structure function at high x can explain the large rate for high
p_T photon plus charm-jet events observed at the Tevatron and imply a large
production rate for charm and bottom jets at high p_T at the LHC, as well as a
novel mechanism for Higgs and Z^0 production at high x_F. The light-front
wavefunctions derived in AdS/QCD can be used to calculate jet hadronization at
the amplitude level. The elimination of the renormalization scale ambiguity for
the QCD coupling using the scheme-independent BLM method will increase the
sensitivity of searches for new physics at the LHC. The implications of
"in-hadron condensates" for the QCD contribution to the cosmological constant
are also discussed.Comment: Invited talk, presented at the 5th Workshop on High P_T Physics at
the LHC held at the Instituto de Ciencias Nucleares of the Universidad
National Automata de Mexico in Mexico City, September 27-October 1, 201